Means for roll forming annular parts

ABSTRACT

Rolling apparatus comprising a female die to receive an annular blank, and a male rolling die impinging on the blank interiorly thereof, with movable backup, driving and rotating members for each die.

United States Patent Howard A. Greis Holden, Mass. 761,073

Sept. 20, 1968 Apr. 27, 1971 Kinefac Corporation Worcester, Mas.

Inventor Appl. No. Filed Patented Assignee MEANS FOR ROLL FORMING ANNULAR PARTS 3 Claims, 5 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 3,230,606 1/1966 Saito et a1. 29/] 48.4 3,345,845 10/1967 Marcovitch et al 72/87 3,382,693 5/1968 Rozhdestvensky et al.... 72/87 3,434,322 3/1969 Cowles et a1 72/107 3,469,427 9/1969 Rollins 72/91 Primary Examiner-Lowell A. Larson Attorney-Charles R. Fay

ABSTRACT: Rolling apparatus comprising a female die to receive an annular blank, and a male rolling die impinging on the blank interiorly thereof, with movable backup, driving and rotating members for each die.

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PATENTED m2 11971 SHEET 1 OF 2 Howard 19. Greeks 2 M MEANS FOR ROLL FORMING ANNULAR PARTS BACKGROUND OF THE INVENTION At the present time the great preponderance of outer bearing races and similar parts are produced at slow rates of speed on automatic screw machines from tubing or bar stock. This results in significant quantities of wasted material, low fatigue, undesired grain structure, high tool costs, and low productivity.

To improve this process, attempts have been made on conventional ring rolling equipment to simultaneously roll form an inner shape and outer shape on a cold formed, sheared, or other blank. However, in most of these attempts using a straight two roll system, the blank when passing through the nip of the roll tends to elongate circumferentially more rapidly than it flows inward radially. The result is loss of control of the ring diameter and inability to control the roundness of the finished part. Various attempts have been made to improve this process by putting outboard rounding rolls around the ring and sensing when it reaches approximately correct size, and quickly stopping the rolling. This resulted in some improvement but is not practical for smaller diameter races of 3 inches under. Since the bulk of the bearing races are in this smaller size range, new means were required to permit the effective application of chipless machining to this class of part. In addition to overcoming the diameter and roundness problem, any new means which was directed toward the rolling of small diameter outer races also would of necessity have to solve the problem of large bending loads on the inner (male) die or mandrel.

SUMMARY OF THE INVENTION This invention eliminates the above-mentioned problems as well as providing a number of other significant advantages. In this new rolling system, an essentially cylindrical or annular blank is placed inside a female die whose inside diameter is predetermined and has at one end an axial constraint and forming rib. A male die is then inserted interiorly of the blank and a pair of driven rolls engage the female die at one side and the male die at the opposite side, forcing the two together and providing rotational torque, until such time as both of the backup dies engage the male die or the arbor therefor, limiting the action. There are also included ejection means as to the two backup dies are moved apart after the rolling operation is finished, and the finished rolled annular part after ejection will spring outwardly uniformly in a repeatable manner to an amount which is proportional to the circumference of the part times yield point of the material, divided by Youngs Modulus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in front elevation illustrating the invention;

FIG. 2 is a similar view on a larger scale with parts omitted and parts in section;

FIG. 3 is a plan view partly in section;

FIG. 4 is a view similar to FIG. 3 on an enlarged scale with parts omitted; and

FIG. 5 is a sectional view illustrating the proportions of the final product.

PREFERRED EMBODIMENT OF THE INVENTION Referring now to FIGS. 1 and 2, the entire machine may be based on the die rolling machine disclosed in US. Pat. No. 3,269,161. A table or base such as is indicated by the numeral is provided and a pair of spaced bearings (not shown) are on this table and mount a shaft 14. Mounted to swing on this shaft are a pair of arms or heads 16 and 18 generally of C- shape and provided with opposed faces at 20, 20 upon which rolls 22 and 23 are mounted. The right-hand roll 22 is a control roll and the left-hand roll 23 is a driving roll, as will be made more clear hereinafter.

The initial blank is annular. This is indicated at 24, FIGS. 2 and 3. This blank is set into an annular female rolling die 26 which has an interior diameter slightly larger than that of the outside of the blank and is also provided with a constraint shoulder which again is annular, and it is therefore capable of constraining the blank being rolled to a specific diameter and roundness.

This female die 26 is located in its initial position between rolls 22 and 23. The right-hand roll contains three basic sections. The rear end section 30 and the front end section 32 serve as both axial constraints for the female die 26, and their outer surfaces serve as a final size stop for the internal male die 28. The center section 34 has a bearing 35 on which is a sleeve 37 supplying the right-hand component of the rolling load to the female die. In addition, the forming lip 38 on the front of the roll 22 shapes the front corner of the outside of the rolled part as it expands axially during rolling.

The left-hand roll 23 which is mounted on the other spindle of the rolling machine also consists of two different diameter sections. The two large diameter areas front and rear 40, 40 provide the left-hand component of the rolling load to the internal male die at both sides of the female die, thereby eliminating any overhung loading. The female die is held vertically on the approximate center line between the two rolls as by a spring-return pivoting shoe or arm 42 having an adjustable stop 43. There is some kind of top constraint 32. In addition the same units hold the female die on the horizontal centerline of the machine when it is in its unloaded position. The internal male die 28 is located in a rotatable but axially constrained mounting on the horizontal centerline of the rolling machine, see FIG. 3.

The two sections 40, 40 of the left-hand roll 23 in front and behind the female die 26 provide the rolling force by engaging with the body of the male die. In addition, at the conclusion of the rolling cycle they provide the penetration stoppage by engaging the right-hand roll 22. The central secton between them contains the profile P as clearly shown, FIG. 5, which will be rolled into the inside diameter of the part being formed. The two sections 40, 40, together with the other two sections 30 and 32 provide axial constraint to the female die 34.

Concentric to the male die 28 and mounted so that it can be actuated with great force axially with respect to the female die is an ejector sleeve 45. In addition in those cases where the machine is fitted for automatic operation, there is also a concentric injector sleeve 46 located on the centerline of the machine directly in front of the die system. In typical automatic operation, the unrolled blanks come down a supply track, the injector sleeve 46 moves forward stripping a blank out of the supply track and placing it in the rolling position within the female die. The right-hand roll advances, bringing the female die leftward so that the blank within it contacts the forming profile on the internal male die 28.

Simultaneously the left-hand roll comes in and provides rotational drive to the internal male die by friction on the supporting surfaces while holding it on the centerline of the rolling machine. The left-hand roll remains in that position while the right-hand roll continues its forward movement driving the blank being formed further into the profile of the male die. This process continues until stop surfaces on the right-hand roll contact stop surfaces on the male die, at which point the rotation continues for three or four revolutions to make sure that the plastic deformation is complete and uniform all the way around the part being formed. When it is complete, the rolls 23, 23 are returned] to their home position by the rolling machine in its typical rolling cycle. The centering and supporting arm 42 returns the female die to a position concentric with the internal male die, and the ejection sleeve is actuated forward to strip the finished rolled part 48 'out of the female die. It falls into a chute and from thence into some kind of tote pan. The sequence is then repeated. It should be noted that with a well designed rolling machine and feed, this sequence can be repeated as many as 30 or 40 times per minute.

The finished rolled part after ejection will spring outward uniformly in a highly repeatable manner an amount which is proportional to the circumference times the yield point of the material divided by Young's Modulus Therefore as indicated earlier, the bore of the female die is made to a dimension equal to the finished outside diameter desired minus the aforementioned amount. it may also be compensated for the stretch of rings itself if the cross section of the ring female die is substantially less the cross section of the part being rolled.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

I claim:

1. Apparatus for roll forming an annular form on the inside diameter of a hollow cylindrical blank comprising a female die enveloping the blank, a roll on one side of the blank which applies horizontal force to the female die, a male die, another roll which provides both rotation and horizontal force to drive the male die into the cylindrical blank interiorly thereof while all the members of the system are rolling, and ejection means with sufficient power to force the rolled blank within the female die out of the die at the end of the rolling cycle.

2. The apparatus of claim 1 wherein the ejection means comprises an axial sleeve concentric with the internal male die.

3. The apparatus of claim 1, wherein the rolls are positioned to provide axial constraint to the female die during the pushout cycle. 

1. Apparatus for roll forming an annular form on the inside diameter of a hollow cylindrical blank comprising a female die enveloping the blank, a roll on one side of the blank which applies horizontal force to the female die, a male die, another roll which provides both rotation and horizontal force to drive the male die into the cylindrical blank interiorly thereof while all the members of the system are rolling, and ejection means with sufficient power to force the rolled blank within the female die out of the die at the end of the rolling cycle.
 2. The apparatus of claim 1 wherein the ejection means comprises an axial sleeve concentric with the internal male die.
 3. The apparatus of claim 1, wherein the rolls are positioned to provide axial constraint to the female die during the pushout cycle. 